making 6.4.1-pre-July-12 by itself

There appears some package conflict problem in re-making  
ghc-6.4.1-pre  with itself 
(under  Debian Linux).

On  July 12, 9.00 GMT,  I downloaded   ghc-6.4.1-pre of CVS

and `made' it with          ghc-6.4.1-pre-June-14.
It looks working all right.

Then I downloaded  ghc of 5 hours later:
ghc-6.4.1-pre  of CVS of  July 12, 14.00 GMT.

I reset the path to the  July-12 install place,
and for more safety, move the installation directory  of  June-14
to other place.

> which ghc
/home/mechvel/ghc/cvs/pre6.4.1/inst/bin/ghc

> which ghc-pkg
/home/mechvel/ghc/cvs/pre6.4.1/inst/bin/ghc-pkg

-- this is  ghc-July12-9.00,  as needed.

Now, `making'  ghc-July12-14.00 with ghc-July12-9.00 
reports

---------------------
...
...
/home/mechvel/ghc/cvs/pre6.4.1/inst/bin/ghc -H16m -O -I. -Iinclude 
-Rghc-timing  -I../../../libraries -fglasgow-exts -no-recomp 
   -c System/Directory/Internals.hs -o System/Directory/Internals.o 
 -ohi System/Directory/Internals.hi

System/Directory/Internals.hs:1:0:
    conflict: module `System.Directory.Internals'
    belongs to the current program/library and also to package base-1.0
<<ghc: 18868296 bytes, 5 GCs, 79280/79280 avg/max bytes residency 
(1 samples), 16M in use, 0.02 INIT (0.00 elapsed), 
0.16 MUT (0.21 elapsed), 0.08 GC (0.10 elapsed) :ghc>>
make[4]: *** [System/Directory/Internals.o] Error 1
make[3]: *** [boot] Error 2
make[2]: *** [boot] Error 1
make[1]: *** [boot] Error 1
make[1]: Leaving directory
`/home/mechvel/ghc/cvs/pre-6.4.1-July-12/fptools/ghc'make: *** 
[build] Error 1
-------------------------------------------------------

What we have to do with this, please?

-----------------
Serge Mechveliani
mechvel@xxxxxxxx